All of the ecards at Care2 support environmental causes.
They have a huge selection of thousands of beautiful ecards for lots of different occasions - some animated and others video ecards.
You can filter the results by "Special Features" and choose "Free Designs" to see just the free ones.
Ojolie is another place you can visit for free ecards, and while there are lots of ecards to look at, there's a rather sparse selection of free ones. Select one to get a full-screen view of the card and to play out the animation, and then choose the "Send this free card" link at the top of the ecard to customize the greeting voice and message.You can send Ojolie's free animated ecards to up to 40 people at once and do so immediately or on a future date.
If you want to mail a greeting card, I also have a list of free, printable greeting cards for just about every occasion.
Punchbowl is my favorite free ecard website because not only will you find beautiful free ecards here, their website is extremely easy to use.
The free ecards at WWF can be sent on any day you want and to multiple recipients simultaneously.
You can even include a gift card along with your ecard.
Tip: Punchbowl's free ecards are the ones with the blue circle that says "Free" at the top.
You'll get to personalize the free ecards at Pingg with your own custom text like the event name and time, location, address, and a message to the recipient.
Besides free ecards, Pingg also has free online invitations that you can send for any event that you are having and allows you to collect your RSVP's straight from Pingg to your email.